Geometrical Destabilisation of Ultra-Light Axions in String Inflation. (arXiv:1903.01497v1 [hep-th])
<a href="http://arxiv.org/find/hep-th/1/au:+Cicoli_M/0/1/0/all/0/1">Michele Cicoli</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Guidetti_V/0/1/0/all/0/1">Veronica Guidetti</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Pedro_F/0/1/0/all/0/1">Francisco G. Pedro</a>
We perform a detailed analytical and numerical analysis of the multi-field
evolution of Fibre Inflation and show that, regardless of the microscopic
realisation of the model, the mass-squared of one of the two ultra-light axions
becomes always negative during inflation. This implies that the corresponding
isocurvature perturbations experience a potential geometrical destabilisation
which seems to bring the system away from the perturbative regime. Therefore we
conclude that a full understanding of the inflationary evolution of Fibre
Inflation can be achieved only via a non-perturbative analysis where the
backreaction of tachyonic isocurvature perturbations is properly taken into
account.
We perform a detailed analytical and numerical analysis of the multi-field
evolution of Fibre Inflation and show that, regardless of the microscopic
realisation of the model, the mass-squared of one of the two ultra-light axions
becomes always negative during inflation. This implies that the corresponding
isocurvature perturbations experience a potential geometrical destabilisation
which seems to bring the system away from the perturbative regime. Therefore we
conclude that a full understanding of the inflationary evolution of Fibre
Inflation can be achieved only via a non-perturbative analysis where the
backreaction of tachyonic isocurvature perturbations is properly taken into
account.
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